Systems for radiation curing or drying of articles and, in particular, ultraviolet curing of printed or coated can bodies, are well known in the art. Typically, they consist of an ultraviolet generating lamp and a conveyor for moving the wet bodies along an irradiated travel path.
During temporary stoppages or shutdown periods, it is desirable to maintain the UV lamps in an operating mode, so as to minimize curing lag when operation resumes. However, to prevent over-curing of the stationary can bodies exposed to the lamp during such periods, it has been the practice to shield the bodies by means of an air- or water-cooled, solid shutter. Unfortunately, the prior art shutters have been found to be unsatisfactory in some respects, and in particular because they block air circulation to the lamp, thus preventing heat dissipation and thereby diminishing the life of the lamp and the efficiency of its operation. Moreover, warpage due to thermal expansion has been a rather serious problem with such equipment.
Accordingly, it is an object of this invention to provide a novel shutter which serves as a highly effective light barrier, while permitting the free flow of air therethrough.
It is also an object of this invention to provide such a novel shutter which is of reduced susceptibility to the adverse effects of heat and, in particular, distortion caused by thermal expansion, and is of relatively simple construction, durable, and readily- and easily-operable.
It is still another object of this invention to provide a novel system for effecting the radiation curing of conveyed articles and, in particular, the UV-curing of can bodies, in which such a novel shutter of the foregoing description may be employed.
It is yet another object of this invention to provide such a system which is relatively simple, durable, dependable and efficient in operation.